This K23 proposal combines focused coursework, a substantial research plan, and close personal mentoring to train Susan Huang, M.D., M.P.H. for independence as a clinical investigator. Dr. Huang is currently an Instructor in Infectious Diseases who has a long-standing interest in bacterial antibiotic resistance and hospital epidemiology. This project will develop and test methods to guide more effective control of nosocomial transmission of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococcus (VRE) in the intensive care unit (ICU) setting. Specifically, it will introduce an alternative monitoring method and assess its ability to identify periods of high MRSA and VRE transmission when compared to current methods, b) evaluate the use of carriage pressure to predict transmission and control for the non-independent (contagious) nature of infectious agents, c) re-evaluate the association of potential predictors of transmission after controlling for carriage pressure, and d) develop and implement an improved monitoring system which warns of high risk potential and activates an intervention to prevent transmission of MRSA and VRE. Methods will include state-change transmission models, observational cohort, case cohort, and prospective cohort designs. Mentors will include experts from the fields of infectious diseases and epidemiology (Richard Platt, M.D., M.S., Brigham & Women's Hospital, Harvard Medical School), and mathematics and infectious diseases transmission modeling (Marc Lipsitch, Ph.D., Harvard School of Public Health). This project will provide foundational knowledge about the validity of regression techniques for non-independent infectious outcomes, and evaluate the impact of an intervention to stem health care associated transmission of MRSA and VRE.